My current issue is twofold - I have been trying to test a solution, but can't get it to work. Of course, even if I can implement my idea, it may not solve the issue.

Currently, when using the TsiLang MessageDlg function in CBuilder, the text will not display if it contains an umlaut. The box will have the right dimensions for the text, but the text itself is not there. I tested multiple scenarios to eventually prove that the umlaut is somehow the cause.

Since other issues with umlauts were related to not using a suitable font, I have been trying to change the font displayed in the message boxes, but have not been able to find a good solution.

I read in a previous post that the module should use the same font as the form to display the text in a message dialog, but I have played around with different fonts to no avail.

So, my questions are as follows:

1. Am I right that the font is causing the text to not display when there are umlauts? If not, what else may be causing this issue, and how do I resolve it?

Hello,
I'm not sure if I understood properly but do you mean that when there are umlauts in text the whole text is missing in message box or just umlauts get corrupted while display?
If the last one then:
The most possible origin of the problem is that you didn't specify the Charset setings for the form's Font property. Font name configures the font to use but Charset configures the script. For west-europenean languages with umlauts it should be ANSI_CHARSET. TsiLang uses the parent form's font property and assigns it to the font of MessageDlg() form.

The entirety of the text is missing. The box has a heading, buttons and icon, but the actual body text is not there. It's fine without umlauts, but if I put an umlaut in the translation and run it again, the body is blank.

I tried changing the charsets associated with the form, but they're already set to ANSI_CHARSET.

I've tried it out in a small sample program, but I can't get the error to occur yet. Someone else in the organisation has a full source licence, so I'll see if I can have a look at it with them and hopefully make some progress.